Instant electrode water heater

ABSTRACT

An instant electrode water is provided. The instant electrode water heater comprises a housing for containing water therein with the housing having a water inlet and a water outlet. A plurality of electrode plates is disposed inside the housing. The electrode plates are placed such that the electrode plates are oriented parallel to each other and have a predetermined distance between two successive electrode plates for directing water received at the water inlet through successive channels, with each channel being formed by two successive electrode plates, to the water outlet. A plurality of electric contacts is disposed in the housing such that each electric contact is in a touching relationship with a respective electrode plate for providing AC electric power thereto. Electric control circuitry is connected to the electric contacts for controllably providing electric power thereto. The electrode plates may be contained in an electrode cartridge which is removably disposed in a cavity of the housing. The electric control circuitry may comprise current sense circuitry for providing a current sense signal indicative of an electric power usage of the electrodes. A microcontroller is connected to the current sense circuitry, an AC electric power supply, and a user interface. The microcontroller determines supply of the AC electric power to the electrodes in dependence upon the current sense signal and the user input signal and provides a supply control signal indicative of the supply of the AC electric power to the electrodes to the AC electric power supply.

FIELD

The present invention relates to electric water heaters, and more particularly to an instant electrode water heater that is compact and provides hot water at a substantially high speed and efficiency.

BACKGROUND

Due to high—and further increasing—energy costs, there is an increasing demand in energy efficient electric water heaters. In particular, there is an increasing demand in instant—or on-demand—electric water heaters that heat water only when hot water is being used. Since the instant electric water heaters are more energy efficient and use less space than storage tank electric water heaters, they are preferred for various household and industrial applications such as, for example, showers, and appliances such as, for example, coffee makers, dish washers, and washing machines.

Most prior art tankless water heater systems use resistance type electric heating elements to heat the water. A major disadvantage of tankless water heater systems utilizing resistance type electric heating elements is that the elements themselves have substantial thermal mass and thermal resistance, substantially reducing the speed the water is heated, especially when the water flow is started. Since the water must flow through the heater before the heating element is activated and the heating element requires time to heat the water, there is first cold water flowing out of the heater, which is particularly a disadvantage in applications without a drain such as, for example, coffee makers.

The alternative to using heating elements for heating the water is to pass an electric current through the water by passing it between two electrodes between which an AC voltage exists, known as Direct Electrical Resistance (DER) heating. Unfortunately, existing instant electrode water heaters have numerous disadvantages: they are highly complex, rendering them expensive to manufacture and difficult to implement in a compact fashion; the hot water temperature is difficult to control; and, they have a relatively high lifetime cost since the complete heater has to be replaced when the electrodes are no longer functional due to corrosion and/or mineral deposition.

It may be desirable to provide an instant electrode water heater that is simple and compact.

It also may be desirable to provide an instant electrode water heater that provides hot water at a substantially high start-up speed and efficiency.

It also may be desirable to provide an instant electrode water heater that enables substantially accurate control of the hot water temperature.

It also may be desirable to provide an instant electrode water heater that enables simple replacement of the electrodes.

SUMMARY

Accordingly, in one case the present invention provides an instant electrode water heater that is simple and compact.

The present invention may also provide an instant electrode water heater that provides hot water at a substantially high start-up speed and efficiency.

The present invention may also provide an instant electrode water heater that enables substantially accurate control of the hot water temperature.

The present invention may also provide an instant electrode water heater that enables simple replacement of the electrodes.

According to one aspect of the present invention, there is provided an instant electrode water heater. The instant electrode water heater comprises a housing for containing water therein with the housing having a water inlet and a water outlet. A plurality of electrode plates is disposed inside the housing. The electrode plates are placed such that the electrode plates are oriented parallel to each other and have a predetermined distance between two successive electrode plates for directing water received at the water inlet through successive channels, with each channel being formed by two successive electrode plates, to the water outlet. A plurality of electric contacts is disposed in the housing such that each electric contact is in a touching relationship with a respective electrode plate for providing AC electric power thereto. Electric control circuitry is connected to the electric contacts for controllably providing electric power thereto.

According to one aspect of the present invention, there is provided an instant electrode water heater. The instant electrode water heater comprises a housing having a water inlet and a water outlet and forms a cavity therebetween. An electrode cartridge having a plurality of electrodes therein is removably disposed in the cavity. A cover is removably mounted to the housing in a water sealed fashion for covering the cavity with the electrode cartridge disposed therein. Electric control circuitry is connected to the electrodes for controllably providing AC electric power thereto.

According to one aspect of the present invention, there is provided an instant electrode water heater. The instant electrode water heater comprises a housing having a water inlet and a water outlet and forms a cavity therebetween. A plurality of electrodes is disposed in the cavity. Electric control circuitry is connected to the electrodes for controllably providing AC electric power thereto. The electric control circuitry comprises current sense circuitry for providing a current sense signal indicative of an electric power usage of the electrodes. A microcontroller is connected to the current sense circuitry, an AC electric power supply, and a user interface. The microcontroller determines supply of the AC electric power to the electrodes in dependence upon the current sense signal and the user input signal and provides a supply control signal indicative of the supply of the AC electric power to the electrodes to the AC electric power supply.

An advantage of the present invention is that it provides an instant electrode water heater that is simple and compact.

A further advantage of the present invention is that it provides an instant electrode water heater that provides hot water at a substantially high start-up speed and efficiency.

A further advantage of the present invention is to provide an instant electrode water heater that enables substantially accurate control of the hot water temperature.

A further advantage of the present invention is to provide an instant electrode water heater that enables simple replacement of the electrodes.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the present invention is described below with reference to the accompanying drawings, in which:

FIGS. 1a and 1b are simplified block diagrams illustrating perspective front views of an instant electrode water heater according to one embodiment of the invention;

FIG. 1c is a simplified block diagram illustrating a perspective rear view of the instant electrode water heater according to one embodiment of the invention;

FIG. 1d is a simplified block diagram illustrating a cross-sectional view of the electrode cartridge of the instant electrode water heater according to one embodiment of the invention;

FIG. 1e is a simplified block diagram illustrating a front view of an electrode of the instant electrode water heater according to one embodiment of the invention;

FIGS. 1f to 1h are simplified block diagram illustrating cross-sectional views of details of the instant electrode water heater according to one embodiment of the invention;

FIG. 1i is a simplified block diagram illustrating a cross-sectional view of the electrode cartridge of the instant electrode water heater according to one embodiment of the invention;

FIG. 1k is a simplified block diagram illustrating a cross-sectional view of the housing of the instant electrode water heater according to one embodiment of the invention;

FIGS. 1l and 1m are simplified block diagrams illustrating a top view and a side view of a heat sink element of the instant electrode water heater according to one embodiment of the invention;

FIGS. 2a and 2b are simplified block diagrams illustrating an electric control circuitry of the instant electrode water heater according to one embodiment of the invention;

FIGS. 2c to 2i are simplified block diagrams illustrating components of the electric control circuitry of the instant electrode water heater according to one embodiment of the invention;

FIG. 3a is a simplified block diagram illustrating a side view of an instant electrode water heater according to another embodiment of the invention; and,

FIGS. 3b and 3c are simplified block diagrams illustrating perspective views of a quick connect mechanism of the instant electrode water heater according to another embodiment of the invention.

DETAILED DESCRIPTION

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, certain methods and materials are now described.

While the description of certain embodiments hereinbelow is with reference to a wall mounted instant electrode water heater for providing hot water to, for example, a shower or tap, it will become evident to those skilled in the art that the embodiments of the invention are not limited thereto, but are also adaptable for use in appliances such as, for example, coffee makers, dish washers, and washing machines.

Referring to FIGS. 1a to 1m , an instant electrode water heater 100 according to an embodiment of the invention is provided. The instant electrode water heater 100 comprises an electrically non-conductive housing 102 forming a cavity 112 between water inlet 150.1 and water outlet 150.2. The housing 102 can be mounted to—or forms a single unit with—wall mounting plate 106, which may be mounted to wall 10 in a conventional manner—using, for example, screw fasteners—after connecting water inlet port 126.1 and water outlet port 126.2 to a waterline and electrical port 128 to an electrical supply, as illustrated in FIGS. 1a and 1 b. It is noted that the electrical supply should be surge protected using a fuse or circuit breaker.

Electrodes 130 can be contained in electrode cartridge 114 with the same being removably disposed in the cavity 112. Cover 104 is removably mounted to the housing 102—using, for example, conventional easy to open/close fasteners such as spring latches or magnetic latches 108—for covering the cavity 112 with the electrode cartridge 114 disposed therein in a water sealed fashion using for example, an O-ring seal 120 interacting with a respective sealing surface 122. The electrode cartridge 114, for example, comprises a cartridge housing having a bottom wall and sidewalls which, in concert with the cover 104, substantially completely enclose the electrodes 130. Inlet opening 116.1 and outlet opening 116.2 disposed in the sidewalls such that they align with the respective water inlet 150.1 and water outlet 150.2 of the cavity 112 when the electrode cartridge 114 is properly disposed therein, as illustrated in FIGS. 1b and 1d . The substantially complete enclosure of the electrodes 130 in the housing of the electrode cartridge 114 protects the electrodes during handling of the electrode cartridge 114 by a user when removed from a protective packaging and inserted into the cavity 112, as well as facilitates the proper insertion of the same. Handling and insertion of the electrode cartridge 114 is further facilitated by providing the electrode cartridge 114 and the cover 104 as a single unit.

AC electric power is provided to the electrodes 130 via electric cover connector elements 118 disposed in the cover 104 such as, for example, banana plugs or pin plugs, disposed in the cover 104 which are removably mated with respective electric housing connector elements 162 such as, for example, banana jacks or pin jacks disposed in the housing 102 and connected to electric control circuitry 170 disposed in control housing 124 mounted, for example, to the wall mounting plate 106, as illustrated in FIGS. 1 b, 1 d, 1 i, and 1 k. The electric control circuitry 170 receives AC electric power from electrical port 128 connected to an electrical supply and controllably provides AC electric power to the electrodes 130. The electric control circuitry 170 can comprise current sense circuitry for providing a current sense signal indicative of an electric power usage of the electrodes 130 and a microcontroller connected to the current sense circuitry and user interface 110 such as, for example, a dial or touch screen enabling the user to set a desire hot water temperature. The microcontroller then determines the supply of the AC electric power to the electrodes 130 in dependence upon the current sense signal and the user input signal received from the user interface 110. An embodiment of the electric control circuitry 170 will be described hereinbelow.

A cover sensor 164 such as, for example, a Hall Effect sensor can be disposed in the housing 102 for providing a cover sensor signal indicating if the cover 104 or the spring latch is opened or closed to the microcontroller, as illustrated in FIG. 1 k. If the cover sensor signal is indicative of the cover/latch being opened, the microcontroller stops provision of the AC electrical power to the electric housing connector elements 162 until the cover sensor signal is indicative of the cover/latch being closed in order to protect the user from electric shock when replacing the electrode cartridge 114. Optionally, a solenoid valve 154 connected to the electric control circuitry 170 is disposed between the water inlet port 126.1 and the water inlet 150.1. If the cover sensor signal is indicative of the cover/latch being opened, the microcontroller provides a signal to the solenoid valve 154 to shut off the water flow to the water inlet 150.1 until the cover sensor signal is indicative of the cover/latch being closed in order to enable the user to replace the electrode cartridge 114 without shutting off the water supply. Further optionally, the solenoid valve 154 is used to control the water flow to the water inlet 150.1, for example, to reduce the same when a desired hot water temperature cannot be achieved.

Optionally, the electric control circuitry 170 is adapted for sensing a resistance of the electrodes 130 and for providing a message, for example, displayed on user interface 110 when the sensed resistance is indicative of a need for replacing the electrode cartridge 114.

Further optionally, the electrode cartridge 114 is one of a set of different electrode cartridges 114 with the electrodes 130 thereof being adapted for heating water having different conductivity. For example, the electrodes 130 are adapted to different water conductivities by changing the distance D_(E) between the electrodes 130 and/or the size—length L_(E) and width W_(E)—of the electrodes 130, as well as the number of the electrodes 130. With the electric control circuitry 170 being adapted for providing AC electric power to the electrodes 130 of any one of the set of different electrode cartridges 114, the instant electrode water heater 100 is easily adapted for heating water having specific water conductivity, enabling high speed and efficiency. For example, a user provides a water sample for testing the conductivity to his/her retailer of the water heater and can then purchase the appropriate electrode cartridge 114 in dependence upon the test result. This can be done prior purchasing the instant electrode water heater 100, as well as during the lifetime of thereof, for example, when purchasing a replacement electrode cartridge 114 in order to adapt to changes in the water conductivity.

The electrodes 130 can be provided as a plurality of electrode plates 130—having a predetermined length L_(E), width W_(E), and thickness T_(E)—disposed inside the electrode cartridge 114, as illustrated in FIGS. 1d and 1 e. The electrode plates 130 are placed such that they are oriented parallel to each other having a predetermined distance D_(E) between two successive electrode plates 130 for directing water received at the water inlet opening 116.1 through successive channels with each channel formed by two successive electrode plates 130 to the water outlet opening 116.2 with the water being directed to flow in opposite direction in any two successive channels, as indicated by the block arrows in FIG. 1 d. For example, each electrode plate 130 comprises an aperture 132—such as, for example, a circular aperture having a predetermined diameter D_(A)—disposed in one end portion thereof for enabling the water to flow therethrough and wherein the apertures 132 are disposed in opposite end portions of any two successive electrode plates 130. Alternatively, the apertures 132 are replaced by cut-outs in the end portions of the electrode plates 130 or channels disposed in the cartridge housing.

The electrode plates 130 are secured to the electrode cartridge 114 such that the electrode plates 130 are enabled to vibrate in substantially all directions during provision of the AC electric power, which is achieved, for example, by accommodating the electrode plates 130 in respective grooves 134 disposed in the bottom and/or sidewalls of the electrode cartridge 114, with the grooves having a predetermined width WG which is greater than the thickness T_(E) of the respective electrode plates 130 and a predetermined depth DG which is sufficient for securing the respective electrode plates 130 while vibrating, as illustrated in FIG. 1 f. The AC electric power is provided to each of the electrode plates 130 using respective electric contacts disposed in the housing such that each electric contact is in a touching relationship with a respective electrode plate 130. The electric contacts are provided, for example, as pins 140 in contact with the upper end of the electrode plate 130 with a compression spring 142 interposed between electric contact plate 144 disposed in the cover 104 and the pin 140 to ensure electric contact while also enabling the electrode plate 130 to vibrate, as illustrated in FIG. 1g . Alternatively, the electric contacts are provided using spring clips 148 mounted to the cover 104, as illustrated in FIG. 1 h.

Further alternatively, the electric contacts are disposed in the bottom with the electrode plates 130 placed thereupon and touching contact being ensured by placing a flexible material such as, for example, a foam insert between the top of the electrode plates 130 and the cover 104.

The electric contacts are connected to a neutral wire 146.1 and a live wire 146.2 in communication with the neutral electric cover connector element 118.1 and the live electric cover connector element 118.2, respectively, such that the electrode plates 130 are connected to neutral AC and live AC in an alternating fashion, as illustrated in FIG. 1 i.

The housing 102, the cover 104, and the housing of the electrode cartridge 114 are made of a heat resistant and electrically non-conductive material, such as a plastic material such as, for example, Acetal using standard plastic molding techniques. The electrode plates 130 can be made of graphite, manufacturing and installation of which is facilitated by the simple shape of the electrode plates 130 and the touching contact for provision of the electric power. Alternatively, the electrode plates 130 are made of another electrically conductive material such as, for example, aluminum, stainless steel, or brass. Further alternatively, the electrode plates 130 have a different shape such as, for example, a circular shape to conform with a cylindrical housing.

The electrode plates 130 as described hereinabove provide a relatively large amount of electric power—large electrode surface area in contact with the water—to a relatively small amount of water—small channels between the electrode plates 130—compared to conventional instant electric water heaters, enabling a substantially compact instant electric water heater having a substantially high start-up speed and efficiency.

In an example implementation, 10 electrode plates 130 having length L_(E)=57 mm, width W_(E)=51 mm, and spaced at distance D_(E)=1.5 mm are employed to heat 4.51/min of water by 40° C. using 240V at 40-45 A supply power.

Optionally, the electrode cartridge 114 is omitted and the electrode plates 130 are directly disposed in the housing 102.

It is noted that the cartridge assembly may also be implemented with other shapes, arrangements of the electrodes, as well as connecting mechanisms for providing the electric power thereto.

Further optionally, the electric control circuitry 170 disposed, for example, on a Printed Circuit Board (PCB), is cooled using a heatsink element 166 in thermal contact with the PCB, as illustrated in FIGS. 1l and 1 m. The heatsink element 166 comprises a block made of a thermally conductive material such as, for example, copper, having channels 168.1 and 168.3 disposed therein for transmitting water therethrough. The channel 168.1 is connected to the channel 168.3 via conduit 168.2 forming a loop which is connected to the water inlet in order to use the cold inlet water prior provision to the water inlet 150.1. A layer 172 of thermally conducting but electrically insulating material is interposed between the heatsink element 166 and the electric control circuitry 170. The layer 172 may be omitted if the PCB is a surface-mount type PCB or the heatsink element 166 is made of an electrically insulating material.

Referring to FIGS. 2a to 2i , an electric control circuitry 170 for controlling the instant electrode water heater 100 according to an embodiment of the invention is provided. The electric control circuitry 170 comprises current sense and power supply circuitry 170A, connected to the electrodes 130 via in/port 174 and supply power via supply port 176 in communication with electrical port 128. The current sense and power supply circuitry 170A provides a current sense signal indicative of an electric power usage of the electrodes 130 and a microcontroller 170B connected to the current sense circuitry and user interface 110 such as, for example, a dial or touch screen via port 178, enabling the user to set a desire hot water temperature. The microcontroller then controls the supply of the AC electric power to the electrodes 130 in dependence upon the current sense signal and the user input signal received from the user interface 110.

The current sense and power supply circuitry 170A can compromise the following components, as illustrated in FIGS. 2b to 2 i:

-   -   Rectifier 170A.2 transforms AC voltage into rectified DC         voltage;     -   Current sensor 170A.3 uses a low resistance resistor to drop         some voltage off the rectified DC voltage dependent on the power         usage of the electrodes 130 and provides two differential         voltages having a difference proportional to the electrical         power usage of the electrodes 130;     -   H-Bridge 170.4 uses a network of 4 Insulated-Gate Bipolar         Transistors (IGBTs) to invert the input rectified DC voltage         from the current sensor into a custom AC voltage waveform         dependent on the programming of the microcontroller 170B;     -   Gate driver 170A.5 drives the gates of the IGBTs in the H-Bridge         170A.4 dependent on a digital Pulse-Width Modulation (PWM)         signal from the microcontroller 170B;     -   Current sense amplifier 170A.6 takes the two differential         voltages from the current sensor 170A.3 and amplifies the         difference which is measured by the microcontroller 170B; and,     -   Power supply 170A.1 takes the AC supply voltage and provides 12V         and 3.3V output voltages to run the circuitry.

Microcontroller 170B drives the gate driver 170A.5 and reads the voltage output from the current sense amplifier 170A.6 and regulates the power provided to the electrodes 130 based on the voltage output from the current sense amplifier to achieve a set power based on the user input signal or preprogrammed into the microcontroller 170B. The microcontroller is, for example, a suitable off-the-shelf Field-Programmable Gate Array (FPGA) as well as the other components are also off-the-shelf components assembled on a PCB using standard technology.

Optionally, the microcontroller 170B is connected to: the cover sensor 164 via port 180; the solenoid valve 154 via port 182; inlet water temperature sensor 156 via port 184; outlet water temperature sensor 158 via port 186; water flow sensor 160 via port 188; and, water conductivity sensor 161 via port 190.

For example, the microcontroller 170B receives a cover sensor signal indicating if the cover 104 or the spring latch 108 is opened or closed to the microcontroller 170B. If the cover sensor signal is indicative of the cover/latch being opened, the microcontroller 170B stops provision of the AC electrical power to the electric housing connector elements 162 until the cover sensor signal is indicative of the cover/latch being closed in order to protect the user from electric shock when replacing the electrode cartridge 114. The microcontroller 170B may also send a signal to the solenoid valve 154 to shut off the water flow if the cover sensor signal is indicative of the cover/latch being opened. Furthermore, the microcontroller 170B may receive one or more signals indicative of the inlet water temperature, the outlet water temperature, the water flow rate, and the water conductivity in order to, for example: determine the start/stop and the amount of electrical power provide to the electrodes 130 based thereon in addition to the current sense signal to achieve a set hot water temperature; determine if the electrodes 130 need to be replaced and provide a message to the user interface 110 indicative thereof; determine one of the set of different electrode cartridges 114 in dependence upon the provided electrical power and provide a message to the user interface 110 indicative thereof; adjust the provision of electrical power to the electrodes 130 to changes in the water conductivity or to shut off the electrical power if the changes are greater than a predetermined threshold; adjust the provision of electrical power to changes in resistance of the electrodes 130; and, reduce the water flow if a set hot water temperature cannot be achieved.

As is evident to one skilled in the art, the electric control circuitry 170 may also be adapted for controlling other designs of instant electrode water heaters than the instant electrode water heater 100.

Alternatively, the current sense and power supply circuitry 170A described hereinabove is replaced by circuitry using a TRlode for Alternating Current (TRIAC) for sensing the AC voltages and regulate the provision of electrical power to the electrodes using Phase Controlled Dimming. While the TRIAC based circuitry is somewhat simpler it is less efficient, in particular, if not water-cooled.

Referring to FIGS. 3a to 3c , an instant electrode water heater 200 according to another embodiment of the invention is provided. Here, the instant electrode water heater 200 comprises a housing 202 having water inlet port 206A for receiving cold inlet water, water outlet port 208A for providing the heated water, and electrical port 204A. The water inlet port 206A comprises a quick connector element for being easily mated with a respective wall connector element 206B and the electrical port 204A comprises a standard electrical plug for being easily mated with a respective wall outlet 204B. The water inlet port 206A and the electrical port 204A are place in proximity to each other such they are simultaneously mated with their respective counterparts 206B, 204B. The wall connector element 206B can comprise a shut off mechanism for shutting off the water flow when the water inlet port 206A is disconnected therefrom. The wall outlet 204B can also comprise a shut off mechanism for shutting off the electric power supply when the electrical port 204A is disconnected therefrom.

It is noted that the instant electrode water heater 200 may be implemented with the electrode plates 130 and/or the cartridge assembly as well as with various other designs of instant electrode water heaters.

The present invention has been described herein with regard to certain embodiments. However, it will be obvious to persons skilled in the art that a number of variations and modifications can be made without departing from the scope of the invention as described herein. 

What is claimed is:
 1. An instant electrode water heater comprising: a housing for containing water therein, the housing having a water inlet and a water outlet; a plurality of electrode plates disposed inside the housing, the electrode plates being placed such that the electrode plates are oriented parallel to each other having a predetermined distance between two successive electrode plates for directing water received at the water inlet through successive channels, with each channel being formed by two successive electrode plates, to the water outlet; a plurality of electric contacts disposed in the housing such that each electric contact is in a touching relationship with a respective electrode plate for providing AC electric power thereto; and, electric control circuitry connected to the electric contacts for controllably providing electric power thereto.
 2. The instant electrode water heater according to claim 1 wherein the electrode plates are secured to the housing such that the electrode plates are enabled to vibrate during provision of the AC electric power.
 3. The instant electrode water heater according to claim 2 wherein the electric contacts comprise spring loaded pins or spring clips.
 4. The instant electrode water heater according to claim 1 wherein the electrode plates are graphite electrode plates.
 5. The instant electrode water heater according to claim 1 comprising means for directing the water to flow in opposite direction in any two successive channels.
 6. The instant electrode water heater according to claim 5 wherein each electrode plate comprises an aperture disposed in one end portion thereof for enabling the water to flow therethrough and wherein the apertures are disposed in opposite end portions of any two successive electrode plates.
 7. The instant electrode water heater according to claim 1 wherein the water inlet comprises a quick connector element and wherein an electric connector connected to the electric control circuitry is placed in proximity to the quick connector element such that the quick connector element and the electric connector are simultaneously mated with respective counterparts.
 8. The instant electrode water heater according to claim 1 comprising an electrode cartridge having the plurality of electrode plates contained therein, the electrode cartridge being removably disposed in a cavity of the housing.
 9. The instant electrode water heater according to claim 1 wherein the electric control circuitry comprises: current sense circuitry for providing a current sense signal indicative of an electric power usage of the electrode plates; an AC electric power supply; a user interface for receiving a user input signal; and, a microcontroller connected to the current sense circuitry, the AC electric power supply, and the user interface, the microcontroller for determining supply of the AC electric power to the electrode plates in dependence upon the current sense signal and the user input signal and for providing a supply control signal indicative of the supply of the AC electric power to the electrode plates to the AC electric power supply.
 10. An instant electrode water heater comprising: a housing having a water inlet and a water outlet and forming a cavity therebetween; an electrode cartridge having a plurality of electrodes therein, the electrode cartridge being removably disposed in the cavity; a cover removably mounted to the housing in a water sealed fashion for covering the cavity with the electrode cartridge disposed therein; and, electric control circuitry connected to the electrodes for controllably providing AC electric power thereto.
 11. The instant electrode water heater according to claim 10 comprising a cover sensor connected to the electric control circuitry, the cover sensor for providing a cover sensor signal indicating if the cover is opened or closed.
 12. The instant electrode water heater according to claim 10 comprising a solenoid valve connected to the water inlet and to the electric control circuitry.
 13. The instant electrode water heater according to claim 10 wherein the electrode cartridge comprises a cartridge housing enclosing the electrodes with the housing having an inlet opening for receiving water from the water inlet and an outlet opening for providing the water to the outlet.
 14. The instant electrode water heater according to claim 10 wherein the electrode cartridge is mounted to the cover to form a single unit and wherein the cover comprises electric cover connector elements connected to the electrodes and wherein the electric cover connector elements are removably mated with respective electric housing connector elements connected to the electric control circuitry for providing the AC electric power to the electrodes.
 15. The instant electrode water heater according to claim 10 wherein the electrode cartridge is one of a set of different electrode cartridges with the electrodes thereof being adapted for heating water having different conductivity, and wherein the electric control circuitry is adapted for providing AC electric power to the electrodes of any one of the set of different electrode cartridges.
 16. The instant electrode water heater according to claim 10 wherein the electric control circuitry is adapted for sensing a resistance of the electrodes and for providing a message when the sensed resistance is indicative of a need for replacing the electrode cartridge.
 17. The instant electrode water heater according to claim 10 wherein the electrode cartridge comprises: a plurality of electrode plates, the electrode plates being placed such that the electrode plates are oriented parallel to each other having a predetermined distance between two successive electrode plates for directing water received at the water inlet through successive channels with each channel formed by two successive electrode plates to the water outlet; and, a plurality of electric contacts disposed in the housing such that each electric contact is in a touching relationship with a respective electrode plate for providing AC electric power thereto.
 18. The instant electrode water heater according to claim 10 wherein the electric control circuitry comprises: current sense circuitry for providing a current sense signal indicative of an electric power usage of the electrodes; an AC electric power supply; a user interface for receiving a user input signal; and, a microcontroller connected to the current sense circuitry, the AC electric power supply, and the user interface, the microcontroller for determining supply of the AC electric power to the electrodes in dependence upon the current sense signal and the user input signal and for providing a supply control signal indicative of the supply of the AC electric power to the electrodes to the AC electric power supply.
 19. An instant electrode water heater comprising: a housing having a water inlet and a water outlet and forming a cavity therebetween; a plurality of electrodes disposed in the cavity; and, electric control circuitry connected to the electrodes for controllably providing AC electric power thereto, the electric control circuitry comprising: current sense circuitry for providing a current sense signal indicative of an electric power usage of the electrodes; an AC electric power supply; a user interface for receiving a user input signal; and, a microcontroller connected to the current sense circuitry, the AC electric power supply, and the user interface, the microcontroller for determining supply of the AC electric power to the electrodes in dependence upon the current sense signal and the user input signal and for providing a supply control signal indicative of the supply of the AC electric power to the electrodes to the AC electric power supply.
 20. The instant electrode water heater according to claim 19 wherein the electric control circuitry comprises a rectifier interposed between the current sense circuitry and the electrodes, the rectifier for transforming the AC voltage into rectified DC voltage.
 21. The instant electrode water heater according to claim 20 wherein the current sense circuitry comprises a low resistance resistor for determining the current sense signal by measuring a voltage difference across the low resistance resistor.
 22. The instant electrode water heater according to claim 19 comprising a heatsink element in thermal contact with at least a portion of the electric control circuitry for cooling the same, the heatsink element comprising a channel for transmitting water therethrough with the channel being connected to the water inlet such that the water is transmitted through the heatsink element prior provision to the cavity. 